This invention relates generally to the field of multi-feed antennas. More specifically, a multiple-element antenna is provided that is particularly well-suited for use in Personal Digital Assistants, cellular telephones, and wireless two-way email communication devices (collectively referred to herein as xe2x80x9cmobile communication devicesxe2x80x9d).
Mobile communication devices having antenna structures that support dual-band communication are known. Many such mobile devices utilize helix or xe2x80x9cinverted Fxe2x80x9d antenna structures, where a helix antenna is typically installed outside of a mobile device, and an inverted F antenna is typically embedded inside of a case or housing of a device. Generally, embedded antennas are preferred over external antennas for mobile communication devices because they exhibit a lower level of SAR (Specific Absorption Rate), which is a measure of the rate of energy absorbed by biological tissues. Many known embedded antenna structures such as the inverted F antenna, however, still exhibit undesirably high SAR levels, and may also provide poor communication signal radiation and reception in many environments.
A multiple-element antenna includes a monopole portion and a dipole portion. The monopole portion has a top section, a middle section, and a bottom section. The middle section defines a recess between the top and bottom sections, and the bottom section includes a monopole feeding port configured to couple the monopole portion of the multiple-element antenna to communications circuitry in a mobile communication device. The dipole portion has at least one dipole feeding port configured to couple the dipole portion of the multiple-element antenna to communications circuitry in the mobile communications device. The dipole portion of the multiple-element antenna is positioned within the recess defined by the monopole portion of the multiple-element antenna in order to electromagnetically couple the monopole portion with the dipole portion.